This invention relates generally to the field of integrated circuits mounted on printed circuit boards, and more particularly to methods and apparata for heat dissipation from integrated circuits and printed circuit boards.
As integrated circuits (xe2x80x9cIC""sxe2x80x9d) become increasingly small and carry an increasing number of transistors, heat and heat dispersion become a greater problem. For this reason, computer manufacturers have long used various types of heat distribution systems to attempt to distribute heat and prevent heat buildup on the IC.
One such prior art system is the heat sink. The heat sink is mounted to the top surface of an IC package. The operation of the heat sink is generally as follows: The heat sink is thermally coupled to the top of the integrated circuit package and extends outwardly therefrom. Heat is conducted from the top surface of the IC into the heat sink. The heat sink is configured to provide a relatively great surface area, which in turn facilitates the convective transfer of heat.
The heat sink, while reasonably effective, has several disadvantages. First, heat sinks require a fairly large volume of space, which imposes undesired space limitations on the computer designer. Secondly, the heat sink is thermally coupled only to the top surface of the IC package, providing the underside of the IC package with no heat dispersion other than through convection and the pin-out extending from the IC package.
Another prior art system commonly in use for heat dispersion is the mechanical fan. The fan operates simply by blowing air across the printed circuit board (xe2x80x9cPCBxe2x80x9d), thereby augmenting the convective heat loss. The fan may or may not be used in connection with a heat sink, as described above. While somewhat effective, mechanical fans suffer from frequent mechanical breakdowns. In addition, mechanical fans become less effective as PCB""s and IC packages are more densely configured within the computer system since airflow is diminished.